Currently, environmental and energy resource issues have become hot topics and as a result, an electric vehicle and a plug-in hybrid vehicle are in the spotlight as future transportation means.
Power for battery charge of an existing hybrid electric vehicle has been supplied by driving a generator through a regenerative brake and an engine. However, the electric vehicle and the plug-in hybrid vehicle may be supplied with power for charging a battery from a national power network or a decentralized power supply system.
When the electric vehicle and the plug-in hybrid electric vehicle are used for commuting, a pattern of operation in the morning and charging in the evening significantly adversely affects the national power network or the decentralized power supply system in a predetermined time zone and increases the maximum power consumption amount of the entire power network.
When power greater than the maximum power consumption amount of the entire power network is used, additional generator installation is required for the current power system having a reserve rate of only about 10% and a large amount of electricity may be wasted, which decreases the energy efficiency.
Accordingly, a smart grid system for making a power network intelligent for energy efficiency and energy saving has been currently constructed. A bi-directional vertical supply system such as a micro grid system and the decentralized power supply system is being prepared beyond a vertical system in which electricity is supplied unilaterally from a central system.
A key point of the smart grid system is to enable information to be transmitted and received in real time between consumers and a power company by integrating information technologies such as ZigBee, power line communication, and the like, with the power network. The smart grid system may automatically operate in a corresponding time zone so that a consumer may use electricity when electric charges are cheap.
However, an existing apparatus for charging an electric vehicle immediately performs charging regardless of electric charges, and a charging request time has been focused, which may significantly adversely affect the national power network or the decentralized power supply system. On a user side, a user does not use electricity required for battery charge of an electric vehicle with inexpensive electric charges.